Field
Embodiments of the invention relate to electronic systems, and in particular, to radio frequency (RF) electronics.
Description of the Related Art
Radio communication above 20 GHz is primarily line of sight communication. End fire antennae are used to provide end fire patterns for end to end link between electronic devices, for example in file transfer systems (e.g., downloading from a fixed terminal to a mobile terminal, or mobile-to-mobile communications). Additionally, a good end-fire pattern for 60 GHz ISM band is needed where switching between different patterns to find the best Signal-to-Noise (SNR) ratio.
Two types of end fire antenna designs are currently used, both of which have various drawbacks discussed below. Printed antennae (e.g., Yagi, RPMA, UWB hexagonal, etc.) are one type of end fire antennae. However, printed antennae suffer from poor bandwidth in some designs, low gain and sensitivity to parallel conductive planes. Aperture antennae are another type of end fire antennae. However, existing aperture antennae result in a tradeoff between effective bandwidth and size of the package. As the height of the package is decreased, the effective bandwidth is also reduced. Further, existing technology does not allow for a low form factor aperture antenna, and existing aperture antennas have very complex structures.
In existing end fire antennae, an increase in gain of the antenna requires an increase in size (e.g., thickness) of the antenna, making it difficult to achieve high gain antennae in low form factor applications. Alternatively, a reduction in the thickness of the antenna package results in a reduction in the bandwidth and the gain. Additionally, as the thickness of the package is reduced, the width (longer dimension) of the aperture in an aperture antenna needs to be increased to achieve good directivity, where the directivity is proportional to the aperture area. However, an increase in the width of the aperture results in a reduction in impedance, and can lead to the introduction of Ten0 modes which kill the gain across the bandwidth. The smallest thickness reported in an aperture end-fire antenna, with 57-64 GHz bandwidth is 1 mm, an array of 1×2, and overall size of 14.4 mm×14.4 mm×1 mm, giving a 6 dBi gain.